For the past few decades, the important subject of the tunnel air ventilation (for elimination or minimizing the internal pollutions) has been mostly done by similar conventional methods. That is, the current standards of operation have remained the same and intact. This made the illusion that there were no other ways to solve this problem. The basis of the named method is (and has been) using the ceiling type jet fans, using precise calculations, for capacities and power, which are calculated and selected in accordance to numerous different factors.
The designer, who makes the various calculations and designs, should pay close attention to many different factors, some of which are (the most important ones):
1—Physical aspect of tunnel (length, section, type, directions, mechanical specifications, and the like).
2—Direction and velocity of the wind pressure, speed and direction of the changing wind patterns, and total force of wind energy.
3—Local facilities and availability of power source.
4—The current survey information, such as type of fuel, total consumption of fuels, especially on weekends, and at last, total weight and volume of pollutant that is produced by the cars passing through the tunnel in a 24-hour period, or a fixed amount of time.
5—Approximate separation of the pollutant materials (both physical and chemical, as well as for gases). (Pollution graphical curves showing increasing or decreasing of pollution throughout different times of the day and the weather conditions, and also showing the minimum need for vehicles and people, for using oxygen during the time, while traveling inside of the tunnel.)
6—Bringing attention to all above items and also to the recommendations and technical orders of jet-fans manufacturers. And lastly, the former experiences of similar and past projects, numbers, air capacity, power, and distances (of jet-fans from one another) are examined.
These procedures are normally done and repeated for most of the tunnels, and final result would be selection of a chain of jet-fans placed in the ceiling of the tunnel, in one or two longitudinal axis having certain distances from one another, which draws in the fresh air from one mouth of the tunnel, to the next mouth of it. This is a constant and continuous procedure. This chain of operation is done along the total length of the tunnel and moves the contaminants out of it.
Following are some brief descriptions of disadvantages, weak points, and operational difficulties of Jet-Fan Systems/the conventional system in use today:
1—Financial needs of the system for heavy investment.
2—Substantial weight of the ceiling type jet fans, especially for double type fans, and the cost of special steel hangers.
3—Most importantly, since jet fans operate in chain formation, there are constantly and heavily working and depending on one another. Considering this fact, if one or two units in the chain are inoperable, it will create an operational gap within the system. Additionally, it has a negative effect on the safe and correct chain operation.
4—The Jet-Fan fan system needs a huge amount of cabling, and huge consumption of power, for both normal and backup supplies. The automatic system for the chain has also a complicated wiring network.
5—The system needs to maintain the electrical consumption for the units, which relates to the average consumption of each unit. The total consumption is substantial and the chain needs a high voltage transfer station for itself and its network. Therefore, the running cost of energy consumptions during the years of usage will accumulate to a very large number for the users.
6—Different tunnels are in need of different spare parts, that need substantial budget for different kinds and models, upkeep of units, storage, and operation.
7—Need for clear and precise warranties and specifications and manufacturer guarantees of part's operational integrity. More so, there is a need for higher level of technical skilled labors, which translates into higher wages and thus, bigger annual budgets.
8—A higher level of noise pollution within the tunnel and higher reflectance of sound during operation of the jet-fans (all encompassing).
9—There are limitations within the unit's inspection, maintenance, set-up, and repair of different pieces that may cause temporary shutdown to the tunnel and traffic built-up, which is very costly to public and economy, or sometimes impractical to stop the traffic at all, making the repairs within tunnel impossible or very dangerous for the crew.
10—Since the ceiling fans are hanging from a cement and stone foundations, and they may become loose after a while, due to earth movements or vibration of the fans, there are hidden and probable danger factors from the weight and the vibration of the units (to fall on a vehicle, causing major damages/accidents or death to passengers).
The effect above can be even higher, if the frequency of rotation of all the fans matches the resonant frequency of a principal length or portion or component of the tunnel, which can be an unstable system, with vibrations, with growing amplitude, with increasing the amplitude very quickly. This will cause the whole system collapses, making it very dangerous for people and cars in the tunnel at that time.
11—There are considerable cost and change of designs, plus additional problems, if the design and construction of the chain fan system in some cases are incorrect, to re-do the whole system from scratch again.
12—Special consideration should be given to the pollutant in some countries mixed with the bits of desert sand. The Jet-Fan system has no filtration capabilities, causing the sand to fly like a bullet from the fan blade, with high speed, which can damage the cars seriously and can kill the people upon impact. In addition, designing filters for tunnel air ventilation system is not an easy task. The chain system will not purify the pollutant found in the air and acts as a vacuum.
However, the invention and embodiments described here, below, solve all these problems, and they have not been addressed or presented, in any prior art.